Modulation of a periodic waveform involves modifying a property of the waveform to contain information a user wishes to convey. Two well-known forms of modulation are those used in radio, AM (Amplitude Modulation) and FM (Frequency Modulation). In AM radio, a carrier signal (such as a baseline radio wave) is modified by increasing or decreasing the amplitude of the carrier signal over time, where data is communicated by how much the amplitude is raised. In FM radio, the frequency of the carrier signal varies over time, and based on those frequency changes a user's radio can decode the information being sent. All communications involve some form of modulation to convey information; however, the mediums used for communications can dictate the speed of the communication, as well as how much information can be communicated.
In oil and gas extraction, communicating with the tools located downhole can be critical to operations because knowing the types of rock formations, pressures, temperatures, etc., can affect not only drilling speed, but also surface readiness, planning, and capacity. A common means for communicating with downhole tools is mud-pulse telemetry (i.e., modulating the mud column in the well), which often has data rates as low as 10 bits per second (bps) and is generally slower than the collection of data by the down-hole tool. As a result, any data collected and not yet transferred to the surface must be stored on storage devices located on the tool for future transmission, leading to increased power consumption and tool complexity.